gettimeofday函数

淡淡的烟草味﹌ 2024-04-17 06:29 51阅读 0赞

#include <stdio.h>
    #include <sys/time.h>
    
    int main(){
        struct timeval tv,tv1;
        gettimeofday(&tv,NULL);
        printf("s:%d ms:%d\n",(int)(tv.tv_sec),(int)(tv.tv_usec));
        gettimeofday(&tv1,NULL);
        printf("s1:%d ms1:%d\n",(int)(tv1.tv_sec),(int)(tv1.tv_usec));
        printf("sec:%d  ms:%d\n",(int)(tv1.tv_sec)-(int)(tv.tv_sec),(int)(tv1.tv_usec)-(int)(tv.tv_usec));
    }

![è¿éåå¾çæè¿°][SouthEast]

首先：man gettimeofday中的描述不是很清晰，tv结构体包含usec和sec，调用此函数后获取从1970年(1970.hh.min.sec.usec也就是1970年零点零风零秒)至今的时间换算成sec.usec的格式。所以sec和usec是一个整体。

#include <stdio.h>
    #include <sys/time.h>
    
    int main(){
        struct timeval tv,tv1;
        gettimeofday(&tv,NULL);
        printf("s:%d ms:%d\n",(int)(tv.tv_sec),(int)(tv.tv_usec));
        sleep(3);
        gettimeofday(&tv1,NULL);
        printf("s1:%d ms1:%d\n",(int)(tv1.tv_sec),(int)(tv1.tv_usec));
        printf("sec:%d  ms:%d\n",(int)(tv1.tv_sec)-(int)(tv.tv_sec),(int)(tv1.tv_usec)-(int)(tv.tv_usec));
    }

![è¿éåå¾çæè¿°][SouthEast 1]

如果usec超过1s就会进位到sec中。

一般用于计算程序执行时间段，在计算连接的心跳时间时用的多一些。

[SouthEast]: https://img-blog.csdn.net/20180423142859485?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQvZGlzYWRtaW5pc3RyYXRvcg==/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/SouthEast
[SouthEast 1]: https://img-blog.csdn.net/20180423143426723?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQvZGlzYWRtaW5pc3RyYXRvcg==/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/SouthEast